Modular lance

ABSTRACT

A modular metalmaking lance having a pre-fabricated “plug-in” lower sections. The plug-in section is preferably of sufficient length to ensure that the joint between a plug-in section and an upper lance section is not in the area of the lance that typically is damaged in refining service. At the same time, the plug-in section is preferably short enough to be transported from an off-site assembly/repair shop to the refining shop via standard-length cargo trucks or truck-trailer rigs used throughout the world.

FIELD OF THE INVENTION

[0001] The present invention relates in general to metalmaking processes and equipment and in particular to metalmaking lances for refining metals in a furnace or other vessel.

BACKGROUND OF THE INVENTION

[0002] A vessel for making metal may assume a variety of forms and designations such as a converter, a Linz-Donawitz (LD) converter, an argon oxygen decarburization (AOD) converter, a basic oxygen furnace (BOF), a basic oxygen process (BOP), an electric arc furnace (EAF), a degasser, and so on. For the purposes of the present disclosure, all metal refining vessels requiring, or benefit by the use of, one or more metalmaking lances shall be hereinafter referred to as a “vessel.”

[0003] A metalmaking lance is a long tubular apparatus that injects one or more agents into the vessel, frequently at high velocity, to effectuate combustion, scrap melting, slag treatment, metal refining and other processes and treatments, hereinafter collectively referred to as “refining processes.” A typical lance is constructed of concentrically arranged steel or copper pipe and/or tubing, hereinafter called “pipe” or “pipes.” These pipes are held together by any suitable means, including but not limited to, special or standard fittings joined by screws, bolts, clips, clamps or other mechanical joining arrangements, or welding, brazing or other joining processes involving metal fusion. As is known, depending on the intended use of the lance, it may or may not be cooled by a coolant fluid during operation. Refining metals in a vessel using a lance that is not immersed in the molten metal bath normally requires that the lance be cooled. If cooled, the lance is typically cooled by water that circulates through the passageways between the outer rings of pipes, hereinafter called the “water jacket.”

[0004] The top portion of the lance typically includes a manifold piping arrangement, hereinafter called the “top adapter,” having connections for the attachment of at least one conduit for at least one gaseous, liquid and/or solid agent, hereinafter called “refining agents,” that are required for metal refining processes. If the lance is cooled, the top adapter also includes connections for the attachment of conduits for cooling water.

[0005] Within the lance there are typically one or more internal slip surfaces, either sealed or unsealed, hereinafter called “slip joints,” to allow internal pipe expansion as the outer barrel pipe cyclically heats up and cools down in service, thereby lengthening and shortening as the result of thermal expansion. This internal expansion capability reduces the likelihood that the internal pipes will become stressed beyond their tensile limit and fail in operation.

[0006] The lower portion of the lance consists of the aforementioned pipes, as well as one or more copper components assembled into a lance tip subassembly joined to the pipes by brazing, welding or the like. The lance tip subassembly includes one or more nozzles and/or holes that allow refining agents communicated by the lance to be introduced into the vessel during refining processes.

[0007] The lance is held above the vessel by a suspension device and is lowered into the vessel after materials to be refined, including any required slag-making fluxes and other raw materials, have been charged into the vessel. After being lowered into the vessel, refining agents are introduced. If it is a cooled lance, cooling water also circulates through the lance. The lance remains in service for some usually predetermined time, ranging from minutes to hours, for one refining cycle. After a number of refining cycles, the lance must be removed from the vessel and repaired.

[0008] Lance repair usually consists of replacing worn out or damaged copper components and pipes in the lance. Typically, the lower half of the lance is most vulnerable to damage. In order to reduce costly and inefficient use of the refining facility that employ vessels that require lances for refining processes, it is essential that a source of repaired lances be readily available to the refining facility.

[0009] Conventional lance repair generally involves, but is not restricted to, the following steps: the lance top adapter is removed and exposed slip joints are inspected and repaired or replaced as necessary; the spent lance tip subassembly is removed and exposed slip joints are inspected and repaired or replaced as necessary; damaged lance components are removed and repaired or replaced as necessary; a new or repaired lance tip subassembly is installed; any damaged, worn out or defective seals are installed; the top adapter is reattached; the lance is tested for integrity of welds, fittings and seals; and the repaired lance is returned to the refining shop to await further refining service.

[0010] In the United States and the North American region in general, most lance repair is not done in the refining facility. In these areas, lances are typically sent out to dedicated lance repair shops. This is possible because the highly developed road systems and transport distances in these areas allow specially-equipped trucks to transport loads up to about 25 meters long, which easily accommodates conventional metal refining lances whose lengths normally range from about 14 to 25 meters in length.

[0011] However, in certain geographical areas and under certain unusual circumstances in the United States and North America, as well as in many other regions of the world where refining facilities exist, routine transport of the spent lances is not possible due to inadequate road systems, traffic congestion and/or transport restrictions or excessive hauling distances. Outside of the North American region, for example, it is generally not possible to transport lances greater than about 13.6 meters in length. In these cases, the refining facility has no choice but to perform lance repair in-house. That is, the damaged or spent lance is generally moved to a designated lance repair shop within the refining plant. The repair shop is equipped with various tools, inspection and measuring instruments and devices; testing instruments and devices; cutting, polishing, welding devices; bolt and screw tightening and loosening devices; cleaning devices and materials; sealing devices and materials; engineering drawings and detailed repair instructions and procedures; and components, spare parts, seals, pipes, tubes and lubricants, as well as many operating supplies. Additionally, and quite importantly, highly skilled personnel familiar with all aspects of lance repair must be available whenever required.

[0012] Each component, spare part and/or raw material must be inventoried in sufficient quantity to assure that it is available when required for timely lance repair. All components, spare parts and/or raw materials must be protected from harmful contamination, which may lead to safety or operation problems when the repaired lance is reused. Inspection, testing and measuring devices must be routinely calibrated.

[0013] Because of the foregoing, in-house lance repair is generally more costly than contracted-out repair. Many man-hours must be devoted to the multiple step repair process and many components and other raw materials must be inventoried and maintained. In addition, maintenance personnel who could otherwise be employed more effectively elsewhere in the refining plant are tied up for extended periods of time in duties associated with lance repair. Moreover, in-house repaired lances are often of inferior quality compared to those repaired by specially-qualified and dedicated lance repair personnel. And, under certain unusual instances at refining facilities that normally outsources its lance repairs, the facilities must bear the considerable expense of having outside repair specialists bring equipment and supplies to the facility to perform lance repair on-site.

[0014] Several metal refining lance assemblies are known that have readily detachable and replaceable components. For example, U.S. Pat. Nos. 4,083,539; 4,732,370; 6,022,507 and 6,224,821 disclose various mechanisms for quickly connecting and disconnecting water-cooled metal refining lances to and from their associated top adapters. However, the lance bodies themselves are unitary and therefore not reduced in length by the act of disconnecting them from the top adapters. As a result, for lances that might be of acceptable length for transport in much of the United States and the North American region but not elsewhere, merely disconnecting such lances from their top adapters does not reduce the length of the lances whereby they may be transported via standard-length cargo trucks or truck-trailer rigs used throughout the world. U.S. Pat. No. 6,212,218 describes a water-cooled metal refining lance having a consumable and replaceable refractory tip. While a spent tip may be easily replaced according to this design, its removal from the lance does not materially reduce the length of the lance body. Thus, U.S. Pat. No. 6,212,218 also does nothing to render an oversized lance transportable in geographic areas that accommodate only standard-length cargo trucks or truck-trailer rigs.

[0015] An advantage exists, therefore, for an easily repairable lance and a method of lance repair whereby the repair can be contracted out in geographic regions and under special circumstances where such outsourced lance repair has not previously been possible.

SUMMARY OF THE INVENTION

[0016] According to the invention, lance repair will be affected by supplying the refining shop with modular lances having pre-fabricated “plug-in” lower sections. These plug-in sections are preferably of sufficient length to ensure that the joint between a plug-in section and an upper lance section is not in the area of the lance that typically is damaged in refining service. At the same time, the plug-in section is preferably short enough to be transported from an off-site assembly/repair shop to the refining shop via standard-length cargo trucks or truck-trailer rigs used throughout the world.

[0017] The plug-in sections preferably include the lance tip subassembly and other agent injection components, all internal piping and all internal seals, and water jacket piping if the lance is of the cooled variety. All pipes of the upper section of the lance will be connected to the top adapter since the upper section and top adapter require less maintenance and repair than the lower section. A plug-in lower lance section is connected to and disconnected from an upper lance section at a single joint, which acts may be quickly and easily performed by relatively unskilled workers. Moreover, the present invention eliminates the need for metal refining plants to maintain expensive on-site lance repair shops and skilled lance repair workers.

[0018] Other details, objects and advantages of the present invention will become apparent as the following description of the presently preferred embodiments and presently preferred methods of practicing the invention proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The invention will become more readily apparent from the following description of preferred embodiments thereof shown, by way of example only, in the accompanying drawings wherein:

[0020]FIG. 1 is side elevation view of a modular refining lance constructed in accordance with the present invention; and

[0021]FIG. 2 is an enlarged cross-sectional view of a joint between an upper lance section and a lower lance section of a modular refining lance according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Referring to FIG. 1 there is shown a modular lance according to the present invention identified generally by reference numeral 10. Lance 10 preferably comprises a top adapter 12, an upper section 14 and a plug-in lower section 16 that may be respectively joined to one another at flanged joints 18 and 20 by any conventional metal fusion joining processes such as brazing, welding or the like, or by screws, bolts, clips, clamps or other mechanical joining arrangements.

[0023] As is conventional, top adapter 12 preferably comprises a segmented housing having at least one refining agent inlet that delivers one or more gaseous, liquid and/or solid refining agents to the top adapter from at least one unillustrated source of such agents. Depending on the intended use of lance 10, top adapter 12 may be adapted to convey only one or more refining agents. However, when configured as a cooled lance (as illustrated), the top adapter may comprise a coolant water outlet 22, a coolant water inlet 24 (that are part of a recirculating coolant system) and at least one refining agent inlet 26 that deliver one or more gaseous, liquid and/or solid refining agents to the adapter head from at least one unillustrated sources of such agent(s).

[0024] In such a water-cooled lance, the upper section 14 of lance 10 comprises an outer pipe 30 a and a plurality of concentrically arranged inner pipes 30 b, 30 c and 30 d, etc. (pipe 30 d and any other inner pipes being optional depending upon the intended use of lance 10) defining a plurality of passageways. Likewise, plug-in lower section 16 comprises an outer pipe 32 a and a plurality of concentrically arranged inner pipes 32 b, 32 c, 32 d, etc. corresponding in number and disposition to their counterparts in upper section 14 defining a plurality of passageways that cooperate with the passageways of the upper section. Although the upper and lower lance sections 14,16 are illustrated as having three inner pipes, they may include as few as two inner pipes to thereby define a water jacket and a single refining agent flow passageway. Similarly, they may include more than three inner pipes whereby a water jacket and three or more refining agent passageways may be formed. Likewise, if lance 10 is not water cooled, upper lance section 14 may comprise as few as one outer refining agent pipe defining at least one passageway in communication with the at least one refining agent inlet of top adapter 12. Alternatively, in a non-cooled embodiment of lance 10, upper section 14 may include several refining agent pipes defining a plurality of refining agent passageways for delivering a plurality of refining agent flows from the top adapter.

[0025] As seen in FIG. 2, the several pipes of upper section 14 define a plurality of passageways 34 a, 34 b, 34 c and 34 d, etc. Preferably, passageway 34 a is in communication with coolant water outlet 22, passageway 34 b is in communication with coolant water inlet 24, and at least one additional passageway, e.g., passageways 34 c, 34 d, etc., is in communication with at least one of the refining agent inlet(s) 26. Similarly, the several pipes of lower section 16 define a plurality of passageways 36 a, 36 b, 36 c and 36 d, etc., each of which is in respective fluid communication with a corresponding one of the passageways of the upper section. That is, passageway 36a of lower section 16 is in communication with passageway 34a of upper section 14, passageway 36 b is in communication with passageway 34 b of the upper section, and at least one additional lower section passageway, e.g., passageways 36 c, 36 d, etc., is in communication with the at least one additional passageway, e.g., passageways 34 c, 34 d, etc., of the upper section. The internal pipes of lower section 16 are precisely dimensioned to closely cooperate with the internal pipes of upper section 14. Fluid communication between the cooperating passageways of the upper and lower lance sections is effectively achieved by slip-joints carrying suitable seals such as O-rings or the like which are identified by reference numerals 38 in connection with lower section internal pipe 32 d. As illustrated, lower lance section 16 preferably carries all necessary internal fluid seals; however, as circumstances dictate, upper section 14 may carry selected seals consistent with unique lance design needs and requirements. Preferably, the outermost pair of lance passageways, which are brought into fluid communication with one another by a lance tip subassembly 40, described below, form the coolant water jacket for circulating coolant water through the lance during operation in the manner known in the art. Again, however, if lance 10 is not water cooled, lower lance section 16 may comprise as few as one outer refining agent pipe defining at least one passageway in communication with the at least one refining agent passageway of upper lance section 14. Alternatively, a non-cooled embodiment of lance 10 may include several refining agent pipes defining a plurality of refining agent passageways in communication with the plurality of refining agent passageways of upper lance section 14 for delivering a plurality of refining agent flows, whereby the pipes in the lower section correspond in number and disposition to their counterparts in upper lance section.

[0026] The distal end of the lower section 16 includes lance tip subassembly 40 that is welded, brazed or otherwise integrally connected to the outer pipe 32 a of the lower lance section 16. Depending on the intended use of lance 10, lance tip subassembly 40 may be similarly connected to one or more additional internal pipes of lower lance section 16. Lance tip subassembly 34 includes one or more nozzles and/or holes 42 in communication with the refining agent passageway(s) of the upper and lower lance sections 14, 16 for discharging refining agent(s) communicated by the lance into an unillustrated metalmaking vessel during a metal refining process or processes.

[0027] Lower lance section 16 is preferably of sufficient length to ensure that the joint 20 between lower section 16 the upper lance section 14 is above the area of the lance that typically is damaged in refining service. At the same time, the lower section 16 is preferably short enough to be transported from an off-site assembly shop to a refining facility via standard-length cargo trucks or truck-trailer rigs. To achieve these ends, lower section 16 desirably has a length “L” of between about 6 meters to about 13.6 meters and, more preferably, no greater than about 12 meters.

[0028] Lance repair using the plug-in lower lance sections 16 of the present invention is accomplished as follows. Plug-in sections are transported from a lance assembly/repair plant to a refining plant via standard transportation means used throughout the world. An adequate number of plug-in sections are held in inventory in the refining plant. When a modular lance 10 requires maintenance, the damaged or spent plug-in section 16 is detached from the lance upper section 14 by undoing joint 20 connecting the upper lance section to the plug-in section. The damaged or spent plug-in section is then moved to a holding area at the refining plant to await transport to the off-site assembly shop for refurbishing. Concurrently, all internal seals on the piping of lance top section 14 are inspected and prepared to accept a new or rebuilt plug-in section 16. The new or rebuilt plug-in section 16 is then attached to the lance upper section 14 and the repaired lance is tested. The lance is now ready to be reinstalled in the vessel for refining service.

[0029] The present invention produces several practical time and money saving advantages. For example, the only inventory items required in the refining shop are spare lance plug-in sections and new sealing materials, i.e., the need to maintain an expensive on-site lance repair shop is eliminated. Further, only one joint (joint 20) needs to be assembled, inspected and tested for integrity since all of the intricate and critical pipe alignments and dimensions are previously accomplished when the plug-in section is manufactured or repaired at the off-site lance assembly/repair facility. Thus, the skill level of in-house personnel responsible for replacing the plug-in sections is minimal compared to workers skilled in in-house or on-site lance repair. Additionally, new and used plug-in sections may be easily transported using conventional roads and trucks all over the world.

[0030] Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention as claimed herein. 

What is claimed is:
 1. A modular metalmaking lance comprising: a top adapter comprising a housing having at least one refining agent inlet; an upper lance section comprising at least an outer pipe defining at least one passageway in communication with said at least one refining agent inlet; first joint means for connecting said top adapter and said upper lance section; a lower lance section comprising at least an outer pipe defining at least one passageway in communication with said at least one passageway of said upper lance section; and second joint means for connecting said upper lance section and said lower lance section.
 2. The modular metalmaking lance of claim 1 wherein said lower lance section is no greater than about 13.6 meters in length.
 3. The modular metalmaking lance of claim 1 wherein said first and second joint means comprise flanged joints.
 4. The modular metalmaking lance of claim 3 wherein said flanged joints are joined by metal fusion.
 5. The modular metalmaking lance of claim 3 wherein said flanged joints are joined by mechanical joining arrangements.
 6. A modular metalmaking lance comprising: a top adapter comprising a housing having a coolant water inlet, a coolant water outlet and at least one refining agent inlet; an upper lance section comprising an outer pipe and a plurality of inner pipes defining a first passageway, a second passageway and at least one additional passageway, wherein said first passageway is in communication with said coolant water inlet, said second passageway is in communication with said coolant water outlet, and said at least one additional passageway is in communication with said at least one refining agent inlet; first joint means for connecting said top adapter and said upper lance section; a lower lance section comprising an outer pipe and a plurality of inner pipes corresponding in number and disposition to said outer pipe and said plurality of inner pipes of said upper lance section, said outer pipe and said plurality of inner pipes of said lower lance section defining a first passageway, a second passageway and at least one additional passageway, wherein said first passageway of said lower lance section is in communication with said first passageway of said upper lance section, said second passageway of said lower section is in communication with said second passageway of said upper lance section, and said at least one additional passageway of said lower lance section is in communication with said at least one additional passageway of said upper lance section, said lower lance section further comprising a lance tip subassembly including at least one nozzle in communication with at said least one additional passageway of said lower lance section for discharging at least one refining agent from said lance; and second joint means for connecting said upper lance section and said lower lance section.
 7. The modular metalmaking lance of claim 6 wherein said lower lance section is no greater than about 13.6 meters in length.
 8. The modular metalmaking lance of claim 6 wherein said first and second joint means comprise flanged joints.
 9. The modular metalmaking lance of claim 8 wherein said flanged joints are joined by metal fusion.
 10. The modular metalmaking lance of claim 8 wherein said flanged joints are joined by mechanical joining arrangements.
 11. A lower lance section for use with a modular metalmaking lance, the modular metalmaking lance comprising a top adapter including a housing having at least one refining agent inlet and an upper lance section joined to said top adapter, the upper lance section having at least an outer pipe defining at least one passageway in communication with the at least one refining agent inlet, said lower lance section comprising: at least an outer pipe defining at least one passageway in communication with the at least passageway of the upper lance section, said lower lance section further comprising a lance tip subassembly including at least one nozzle for discharging at least one refining agent from the lance when said lower lance section is joined to the upper lance section.
 12. The lower lance section for use with a modular metalmaking lance claim 11 wherein said lower lance section is no greater than about 13.6 meters in length.
 13. A lower lance section for use with a modular metalmaking lance, the modular metalmaking lance comprising a top adapter including a housing having a coolant water inlet, a coolant water outlet and at least one refining agent inlet and an upper lance section joined to the top adapter, said lower lance section comprising: an outer pipe and a plurality of inner pipes corresponding in number and disposition to an outer pipe and a plurality of inner pipes of the upper lance section, said outer pipe and said plurality of inner pipes of said lower lance section defining a first passageway, a second passageway and at least one additional passageway, wherein said first passageway of said lower lance section is communicable with a first passageway of the upper lance section, said second passageway of said lower section is communicable with a second passageway of the upper lance section, and said at least one additional passageway of said lower lance section is communicable with at least one additional passageway of the upper lance section, said lower lance section further comprising a lance tip subassembly including at least one nozzle for discharging at least one refining agent from the lance when said lower lance section is joined to the upper lance section.
 14. The lower lance section for use with a modular metalmaking lance claim 13 wherein said lower lance section is no greater than about 13.6 meters in length.
 15. A method for assembling a modular metalmaking lance, the modular metalmaking lance comprising a top adapter including a housing having at least one refining agent inlet and an upper lance section joined to the top adapter, the upper lance section having at least an outer pipe defining at least one passageway in communication with the at least one refining agent inlet, said method comprising the steps of: plugging a lower lance section into the upper lance section, said lower lance section comprising at least an outer pipe defining at least one passageway in communication with the at least passageway of the upper lance section, said lower lance section further comprising a lance tip subassembly including at least one nozzle for discharging at least one refining agent from the lance when said lower lance section is joined to the upper lance section; and joining said lower lance section to the upper lance section.
 16. The method for assembling a modular metalmaking lance 15 wherein said lower lance section is no greater than about 13.6 meters in length.
 17. A method for assembling a modular metalmaking lance, the modular metalmaking lance comprising a top adapter including a housing having a coolant water inlet, a coolant water outlet and at least one refining agent inlet and an upper lance section joined to the top adapter, said method comprising the steps of: plugging a lower lance section into an upper lance section, said lower lance section comprising: an outer pipe and a plurality of inner pipes corresponding in number and disposition to an outer pipe and a plurality of inner pipes of the upper lance section, said outer pipe and said plurality of inner pipes of said lower lance section defining a first passageway, a second passageway and at least one additional passageway, wherein said first passageway of said lower lance section is communicable with a first passageway of the upper lance section, said second passageway of said lower section is communicable with a second passageway of the upper lance section, and said at least one additional passageway of said lower lance section is communicable with at least one additional passageway of the upper lance section, said lower lance section further comprising a lance tip subassembly including at least one nozzle for discharging at least one refining agent from the lance when said lower lance section is joined to the upper lance section; and joining said lower lance section to the upper lance section.
 18. The method for assembling a modular metalmaking lance 17 wherein said lower lance section is no greater than about 13.6 meters in length. 